Precision grinding or abrading machine



Sept. 26, 1933. H. H. ASBRIDGE PRECISION GRINDING OR ABRADING MACHINE Filed Aug. 19, 1932 5 Sheets-Sheet l b Hwy 222? Sept. 26, 1933. H. H. ASBRIDGE PRECISION GRINDING OR ABRADING MACHINE Filed Aug. 19, 1932 5 Sheets-Sheet 2 P 1933- H. H. ASBRIDGE PRECISION GRINDING 0R ABRADING MACHINE 5 Sheets-Sheet 3 Filed Aug. 19, 1932 Sept. 26, 1933. H. H. ASBRIDGE PRECISION GRINDING OR ABRADING MACHINE Filed Aug. 19, 1932 5 Sheets-Sheet 4 Mil 52%;

Sept. 26, 1933. H. H. ASBRIDGE PRECISION GRINDING OR ABRADING MACHINE Filed Aug. 19, 1932 5 Sheets-Sheet 5 II II II Patented Sept. 26, 1933 PRECISIONV'GRINDING on ABRADING MAcnrNn Harry Hales Asbridge, Ashton-upon-Mersey, England, assignor to The Churchill Machine Tool Company Limited, Broadheath, near- Manchester, England, a British company Application August 19, 1932, Serial No. 629,521, and in Great Britain ctober'22, 1931 12 Claims.. (o1. 51-165) This invention relates to precision grinding or abrading machines and particularly to the means by which a feed motion is imparted to the grinding wheel head either at each pass of the workpiece when the latter is reciprocated past the grinding wheel, or intermittently when the workpiece carrying the table is stationary during the grinding operation (called plunge cut grinding).

The object of my invention is to provide improved means for imparting the desired feed motion to the grinding head and for tripping it or rendering it inoperative when the workpiece has been reduced to the desired diameter, the said means allowing for an infinitely variable rate of feed between zero and maximum. A further object of 'my invention is to provide means whereby the feed imparted to the grinding head is diminished gradually prior to tripping.

The invention comprises the combination with a roller type ratchet adapted to be wedged against the periphery of a disc by an oscillatory or reciprocatory part in one direction of its movement so as vto drive said disc intermittently and through it the grinding head feed mechanism, of a further roller type ratchet to prevent the disc turning in a reverse direction, and means adapted to move the driving ratchet roller into a position in which 7 it cannot be wedged against the disc so as to trip the drive.

,The invention further comprises the arrange-.

ment wherein both roller ratchets are tripped'to enable the grinding head to be re-set where desired. v

The invention further comprises the improved details of construction and arrangement of parts hereinafter described and claimed. Referring to the accompanying sheetsof explanatory drawings: a

Figure 1 is a front view showing the general arrangement of a feed mechanism in accordance I with my invention.

Figure 2 is a plan view of the parts shown in Figure l 1.

c Figure 3 is a sectional view on the line A B of' The same reference letters in the different views indicate the same parts.

The shaft (1, Figure 2, serves to feed the grinding head by screw and nut or other ordinary means (not shown). Such shaft has a spur wheel I thereon with which gears a wheel 0 upon a shaft d. The latter has a handwheel e thereonandalso a driving disc 1 which is recessed around its peripheral edge to receive two rollersf g and h, which serve respectively as a driving ratchet and a retaining or check ratchet with respect to the driving discf. Upon the shaft (1' are keyed discs 2' and 7', between which is an internally toothed ring is having a lug m thereon. A spindle n journalled in the discs 1' and 7' has a pinion 0 thereon which meshes with the teeth on the ring is, a handle p on the spindle n serving to turn such spindle and so adjust the angular position' of the lug m withrelation to the spindle n which forms the driving connection between the discs '2' and 9' and the ring it.

Mounted upon a sleeve q, which is the bearing sleeve of the shaft a is'a collar like part 1', having teeth s around a portion of its periphery. The collar r is free upon the sleeve q but a spring; pressed pad 5 serves to prevent movement of the. collar relatively to the sleeve otherwise than under the driving action of the lug m or of the handwheel e as hereinafter described. The col-' lar r has' a slide t mounted thereon and movable in a direction parallel with the axis of the shaft afor the purpose of bringing it into the track of the lug m. A collar u secured by a set screw .v to theboss w of the machine frame which contains the bearing sleeve q serves as a stop to limit the rotary movement of the slide t and collar r in a counter-clockwise direction. I V v The teeth s mesh with teeth a: on a part or housing y journalled on the shaft (1 (see Figures 1, 2, 3, and'4). Such housing y forms at z a means of limiting the movement of the driving ratchet roller g in a clockwise direction for the purpose hereinafter described. Upon the housing y is secured a plate 2 (Figure 1) which is parallel to a tangent to the disc f which is within the hous-' ing, and the retaining or check roller ratchet it comes between such plate and the surface of the disc f. A pin 3 secured upon thepart 4 which rides upon the boss of the housing y serves to move the roller it into aposition in which it cannot be wedged between the plate 2 and the disc f. v The part4 is turned by the handle 5 to move the pin 3 into and out of its operative position and has its movement with relation to the housing 3; limited by a pin 6 extending into a slot in y, so

loo

that the handle 5 can serve for moving both the roller 12 and the roller 9 into non-wedging positions.

The driving roller ratchet g is adapted to be wedged against the surface of the disc f by the wedge plate '7 which is oscillated about the axis of the shaft (1 by the link 8. A spring 9 presses a pad upon the roller g to move the latter into its wedging position and the part 2 of the housing y,

as before referred to, serves at appropriate times to move the roller into a non-wedging position. The rod 8 is connected to a lever 9 pivoted at 10. Such lever may be oscillated in known manner by the lever 20 and pusher 21 from stops 11 upon a rod 12 which is moved in one or other direction as the work carrying table (not shown) arrives at the ends of its traverses' Or the said lever 9 may be oscillated by an excentric 13 when the latter is moved into operative position '(by the handle 14) beneath the pad 15 on the end of the lever beneath the rod 8. I

The movement of the rod 8 and the consequent oscillation .of the tangent plate 7. results in the wedging of the roller g against the disc 1 and the turning of the latter in one direction (namely the upward direction) of movement of the rod 8 and the freeing of the roller g from the disc 1 in the downward direction of movement of the W rod. When the disc ,7 is being turned by the roller .on its downward movement.

g, the roller h is being moved out of a wedging position with respect to its tangent plate 2 and the disc, but immediately there is any tendency for the disc ,1 to move backwards or in an anti clockwisedirection, the retaining roller ratchet h wedges itself against the disc 1 and checks it.

The amount of movement imparted by the rod 8 to the tangent plate '7 for each oscillation of the lever 9 may be adjusted by holding up the rod 8 This is effected by means of the crank pin 22 carried in a part 23 integral with the frame carrying the plate 7 which is oscillated about the axis of the shaft d. Such pin can be turned by the knurled head 24 and locked bythe set'screw 25. The pin rests on a fixed bracket 26. If the rod 8 is prevented from falling to its full extent, then there vwill be a certain. amount of lost motion between the excentric l3 and pad 15 or between the pusher 21 and lever 9, which will result in a diminution of the oscillatory movements of the wedgev or tangent plate I'and therefore of the angular advance imparted to thedisc ,f.

The operation of the arrangement is as follows:--Each time the lever 20 is moved the lever 9 is oscillated and the rod 8 raised and lowered. During such movements, the disc I is turned due to the wedging of the roller g between the plate 7 and the disc periphery, and is then looked against a return movement by the roller h. The

the teeth s and ac, the housing 1.1. The part 2' of the latter gradually advances in a clockwise direction towards the roller 9. The initial position is shown in Figure 6. In Figure -7 it will be seen that the part a is close to g and is' in fact limiting the return movement of y when the rod 8 is moving downwards, that is to say the amount of angular movement imparted to the disc f for each upward movement of the rod 8 is being diminished. When the part 2 has reached the Figure 8 position, the roller g is prevented completely from moving into a wedging position between the plate 7 and disc I so that no drive is now imparted to the disc I by the rod 8.

If now it be desired tore-set the parts by hand, the handle 5 is moved to cause the pin 3 to move the roller h into a non-wedging position. Both rollers g and h are now free (as shown inFigure 9) and the hand wheel 6 can be turned to move the shafts d and a to put the grinding wheel head where desired to commence a further grinding operation. At the same time, the ring k carrying the lug m is re-set. When the handle 5 is turned to free the rollers g and h, the former by withdrawing the pin 3 from engagement therewith and the latter by turning the housing 1/ and withdrawing the part ,2 from engagement therewith, at the same time putting the collar r with the slide t in the starting position, the machine is ready for a further cycle of operations.

It will have been noted by reference to Figures 6, '7 and 8 and the description of the operation of the machine, that the extent of feed movement imparted to the shaft it gradually diminishes as thehousing 1 turns to control the initial position of the roller 9. This is a very important advantage of my improved mechanism as it ensures that when the feed is discontinued, the feed drive is freed from torsion strains. In addition, it will havebeen noted that by adjusting the crank pin 22, the extent of feed movement imparted to the disc f for each movement of the rod 8 can be regulated to any desired extent but the feed is always imparted positively due to the definite wedging action of the roller 9.

If the slide 1. be moved clear of the path of the lug m, the trip mechanism for the driving ratchet g is put out of action.

In Figures 69, the parts i 9' lc m and p have been omitted for the sake of simplifying the views.

I may vary the details of my improved mechanism to suit requirements.

' What I claim is:

1. The combination in precision grinding or abrading machines of a shaft connected with the grinding head feed mechanism, a driving disc secured on said shaft, a driving roller ratchet through which said driving disc is driven intermittently from a reciprocatory part of the machine, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, and mechanism carried by said second shaft to reduce gradually and then to prevent the movement of the driving roller ratchet after a predetermined rotary movement of said second shaft.

2. The combination in precision grinding or abrading machines of a grinding head feed mechanism, a shaft connected with said grinding head feed mechanism, a driving disc secured on said shaft, a reciprocatory part of the machine, a driving roller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movementof said driving disc, a second shaft driven from said shaft, and mechanism carried by said second shaft to reduce gradually and then toprevent the movement of the driving roller ratchet after a predetermined rotary movement of said second shaft. 3. The combination in precision grinding or abrading machines of a grinding head feed mechanism, a shaft connected with said grinding head shaft, a reciprocatory part of the machine, a driving roller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, 'a disc driven by said sec-- ond shaft, a part driven by but adjustable with relation to said disc, a lug on said part, a colposition, v i

4. The combination imprecision grinding or abrading machines of a grinding head feed mechanism, a shaft connected with said grinding head feed mechanism, a driving disc secured on said shaft, a reciprocatory part of the machine, a drivingroller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, a disc driven by said second shaft, an internally toothed ring driven by but adjustable with relation to said disc, a lug on said internally toothed ring, a collar adapted to be turned by said lug, and a housing secured to said collar and rotated thereby to move said driving roller ratchet gradually into a non-wedging position.

'5. The combination in precision grinding or abrading machines of a grinding head feed mechanism, a shaft connected with said grinding head fed mechanism, a driving disc secured on said shaft, a reciprocatory part 'of the machine, a driv-,

ing roller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, a disc driven by said second shaft, a part driven by but adjustable with relation to said disc, a lug on said part, a collar adapted to be turned'by said lug, an adjustable slide upon said collar for engagement by said lug, an element moved by said collar, peripheral gear teeth upon said collar, and peripheral gear teeth upon said element engaging said teeth upon said collar to move said driving roller ratchet gradually into a non-wedging position.

6. The combination in precision grinding or abrading machines of a grinding head feed mechanism, a shaft connected with said grinding head feed mechanism, a driving disc secured on said shaft, a reciprocatory part of the machine, a driving roller ratchet through which-said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, a disc driven by said second shaft, an internally tooothed ring driven by. but adjustable with relation to said disc, a lug on said internally toothed ring, a collar adapted to be turned by said lug, an adjustable slideeupon said collar for engagement by said lug, a housing around said driving disc having a part which can engage said driving roller ratchet, peripheral gear teeth upon said collar, and peripheral gear teeth upon said housing engaging said teeth upon said collar to move said mechanism, ashaft connected with said grinding head feed mechanism, a driving'disc secured on said shaft, a reciprocatory part of the ma-' chine, a driving rollerratchetthrough which said drivingdisc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, 9. second shaft driven from said shaft, a disc driven by said second shaft, a part driven bybut adjustable with relation tosaid disc, a lug on said part, a. collar adapted to be turned by said lug, an element moved bysaid collar to'move said driving roller ratchet gradually into a nonwedging position, and a hand operated part upon said element for putting said retaining roller ratchet into and out of operative position and for turning said element to put said driving roller ratchet into and out of operative position and to re-set the mechanism.

8. .The combination in precision grinding or abrading machines ofa grinding head feed mechanism, a shaft connected with said grinding head feed mechanism, a driving disc secured on said shaft, a reciprocatory part of the machine, a driving roller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, a disc driven by said second shaft, an internally toothed ring driven by but'adjustable with relation to said disc, a lug on said internally toothed ring, a collar adapted to be turned by said lug, a housing geared to said collar and rotated thereby to move said driving roller ratchet gradually to a nonwedging position, and a hand operated part upon said housing for putting said retaining roller ratchet into and out of operative position and for turning said housing to put said driving roller ratchet into and out of operative position and to re-set the mechanism.

9. The combination in precision grinding or abrading machines of a shaftconnected with the grinding head feed mechanism, a driving disc secured on said shaft, a driving roller ratchet through which said driving disc is driven intermittently from a reciprocatory part of the machine, means for adjusting the throw of said reciprocatory part, a retaining roller ratchet to prevent reverse movement. of said driving disc, a second shaft driven from said shaft, and mechanism carried by said second shaft to reduce gradually and then to prevent the movement of the a driving roller'ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement of said driving disc, a second shaft driven from said shaft, a disc driven by said,

second shaft, an internally toothed ring driven by but adjustable with relation to said disc, a lug on said internally toothed ring, a collar adapted to be turned by said lug, and a housing secured to said collar and rotated thereby to move said driving roller ratchet gradually into a non-wedging position. a

11. The combination in precision grinding or abrading machines of a grinding head feed mechanism, a-shaft connected'with said grinding head feed mechanism, a driving disc secured on said shaft, 9; reciprocatory part of the machine, a driving roller ratchet through which said driving disc is driven intermittently from said reciprocatory part, a retaining roller ratchet to prevent reverse movement'of said driving disc, and trip mechanism brought into operation to prevent the movementof saiddriving roller ratchet after a predetermined amount/of feed. s

12; In precision grinding. and abrading machines, a feed drive to the grinding wheel head comprising adisc with two roller ratchets thereon, two wedge members for engaging said rollers, one wedge member being fixed and the other member for driving the disc through: a roller, a housing aroundsaid disc with trip mechanism operated from said disc to turn said housing and gradually move the roller engaged by the movable wedge out of a wedging position, a pin mounted upon a hand actuated part upon the housing to move the other rollerout of a wedging position, the said part also moving the housing for re-setting the trip mechanism and for tripping the driving roller ratchet, means adjusting the extent of the back 7 and forth movements of the movable wedge, and. 

